space_map.h revision 339104 
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26/*
27 * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
28 */
29
30#ifndef _SYS_SPACE_MAP_H
31#define	_SYS_SPACE_MAP_H
32
33#include <sys/avl.h>
34#include <sys/range_tree.h>
35#include <sys/dmu.h>
36
37#ifdef	__cplusplus
38extern "C" {
39#endif
40
41/*
42 * The size of the space map object has increased to include a histogram.
43 * The SPACE_MAP_SIZE_V0 designates the original size and is used to
44 * maintain backward compatibility.
45 */
46#define	SPACE_MAP_SIZE_V0	(3 * sizeof (uint64_t))
47#define	SPACE_MAP_HISTOGRAM_SIZE	32
48
49/*
50 * The space_map_phys is the on-disk representation of the space map.
51 * Consumers of space maps should never reference any of the members of this
52 * structure directly. These members may only be updated in syncing context.
53 *
54 * Note the smp_object is no longer used but remains in the structure
55 * for backward compatibility.
56 */
57typedef struct space_map_phys {
58	uint64_t	smp_object;	/* on-disk space map object */
59	uint64_t	smp_objsize;	/* size of the object */
60	int64_t		smp_alloc;	/* space allocated from the map */
61	uint64_t	smp_pad[5];	/* reserved */
62
63	/*
64	 * The smp_histogram maintains a histogram of free regions. Each
65	 * bucket, smp_histogram[i], contains the number of free regions
66	 * whose size is:
67	 * 2^(i+sm_shift) <= size of free region in bytes < 2^(i+sm_shift+1)
68	 */
69	uint64_t	smp_histogram[SPACE_MAP_HISTOGRAM_SIZE];
70} space_map_phys_t;
71
72/*
73 * The space map object defines a region of space, its size, how much is
74 * allocated, and the on-disk object that stores this information.
75 * Consumers of space maps may only access the members of this structure.
76 *
77 * Note: the space_map may not be accessed concurrently; consumers
78 * must provide external locking if required.
79 */
80typedef struct space_map {
81	uint64_t	sm_start;	/* start of map */
82	uint64_t	sm_size;	/* size of map */
83	uint8_t		sm_shift;	/* unit shift */
84	uint64_t	sm_length;	/* synced length */
85	int64_t		sm_alloc;	/* synced space allocated */
86	objset_t	*sm_os;		/* objset for this map */
87	uint64_t	sm_object;	/* object id for this map */
88	uint32_t	sm_blksz;	/* block size for space map */
89	dmu_buf_t	*sm_dbuf;	/* space_map_phys_t dbuf */
90	space_map_phys_t *sm_phys;	/* on-disk space map */
91} space_map_t;
92
93/*
94 * debug entry
95 *
96 *     2     2        10                     50
97 *  +-----+-----+------------+----------------------------------+
98 *  | 1 0 | act |  syncpass  |        txg (lower bits)          |
99 *  +-----+-----+------------+----------------------------------+
100 *   63 62 61 60 59        50 49                                0
101 *
102 *
103 * one-word entry
104 *
105 *    1               47                   1           15
106 *  +-----------------------------------------------------------+
107 *  | 0 |   offset (sm_shift units)    | type |       run       |
108 *  +-----------------------------------------------------------+
109 *   63  62                          16   15   14               0
110 *
111 *
112 * two-word entry
113 *
114 *     2     2               36                      24
115 *  +-----+-----+---------------------------+-------------------+
116 *  | 1 1 | pad |            run            |       vdev        |
117 *  +-----+-----+---------------------------+-------------------+
118 *   63 62 61 60 59                       24 23                 0
119 *
120 *     1                            63
121 *  +------+----------------------------------------------------+
122 *  | type |                      offset                        |
123 *  +------+----------------------------------------------------+
124 *     63   62                                                  0
125 *
126 * Note that a two-word entry will not strandle a block boundary.
127 * If necessary, the last word of a block will be padded with a
128 * debug entry (with act = syncpass = txg = 0).
129 */
130
131typedef enum {
132	SM_ALLOC,
133	SM_FREE
134} maptype_t;
135
136typedef struct space_map_entry {
137	maptype_t sme_type;
138	uint32_t sme_vdev;	/* max is 2^24-1; SM_NO_VDEVID if not present */
139	uint64_t sme_offset;	/* max is 2^63-1; units of sm_shift */
140	uint64_t sme_run;	/* max is 2^36; units of sm_shift */
141} space_map_entry_t;
142
143#define	SM_NO_VDEVID	(1 << SPA_VDEVBITS)
144
145/* one-word entry constants */
146#define	SM_DEBUG_PREFIX	2
147#define	SM_OFFSET_BITS	47
148#define	SM_RUN_BITS	15
149
150/* two-word entry constants */
151#define	SM2_PREFIX	3
152#define	SM2_OFFSET_BITS	63
153#define	SM2_RUN_BITS	36
154
155#define	SM_PREFIX_DECODE(x)	BF64_DECODE(x, 62, 2)
156#define	SM_PREFIX_ENCODE(x)	BF64_ENCODE(x, 62, 2)
157
158#define	SM_DEBUG_ACTION_DECODE(x)	BF64_DECODE(x, 60, 2)
159#define	SM_DEBUG_ACTION_ENCODE(x)	BF64_ENCODE(x, 60, 2)
160#define	SM_DEBUG_SYNCPASS_DECODE(x)	BF64_DECODE(x, 50, 10)
161#define	SM_DEBUG_SYNCPASS_ENCODE(x)	BF64_ENCODE(x, 50, 10)
162#define	SM_DEBUG_TXG_DECODE(x)		BF64_DECODE(x, 0, 50)
163#define	SM_DEBUG_TXG_ENCODE(x)		BF64_ENCODE(x, 0, 50)
164
165#define	SM_OFFSET_DECODE(x)	BF64_DECODE(x, 16, SM_OFFSET_BITS)
166#define	SM_OFFSET_ENCODE(x)	BF64_ENCODE(x, 16, SM_OFFSET_BITS)
167#define	SM_TYPE_DECODE(x)	BF64_DECODE(x, 15, 1)
168#define	SM_TYPE_ENCODE(x)	BF64_ENCODE(x, 15, 1)
169#define	SM_RUN_DECODE(x)	(BF64_DECODE(x, 0, SM_RUN_BITS) + 1)
170#define	SM_RUN_ENCODE(x)	BF64_ENCODE((x) - 1, 0, SM_RUN_BITS)
171#define	SM_RUN_MAX		SM_RUN_DECODE(~0ULL)
172#define	SM_OFFSET_MAX		SM_OFFSET_DECODE(~0ULL)
173
174#define	SM2_RUN_DECODE(x)	(BF64_DECODE(x, SPA_VDEVBITS, SM2_RUN_BITS) + 1)
175#define	SM2_RUN_ENCODE(x)	BF64_ENCODE((x) - 1, SPA_VDEVBITS, SM2_RUN_BITS)
176#define	SM2_VDEV_DECODE(x)	BF64_DECODE(x, 0, SPA_VDEVBITS)
177#define	SM2_VDEV_ENCODE(x)	BF64_ENCODE(x, 0, SPA_VDEVBITS)
178#define	SM2_TYPE_DECODE(x)	BF64_DECODE(x, SM2_OFFSET_BITS, 1)
179#define	SM2_TYPE_ENCODE(x)	BF64_ENCODE(x, SM2_OFFSET_BITS, 1)
180#define	SM2_OFFSET_DECODE(x)	BF64_DECODE(x, 0, SM2_OFFSET_BITS)
181#define	SM2_OFFSET_ENCODE(x)	BF64_ENCODE(x, 0, SM2_OFFSET_BITS)
182#define	SM2_RUN_MAX		SM2_RUN_DECODE(~0ULL)
183#define	SM2_OFFSET_MAX		SM2_OFFSET_DECODE(~0ULL)
184
185boolean_t sm_entry_is_debug(uint64_t e);
186boolean_t sm_entry_is_single_word(uint64_t e);
187boolean_t sm_entry_is_double_word(uint64_t e);
188
189typedef int (*sm_cb_t)(space_map_entry_t *sme, void *arg);
190
191int space_map_load(space_map_t *sm, range_tree_t *rt, maptype_t maptype);
192int space_map_iterate(space_map_t *sm, sm_cb_t callback, void *arg);
193int space_map_incremental_destroy(space_map_t *sm, sm_cb_t callback, void *arg,
194    dmu_tx_t *tx);
195
196void space_map_histogram_clear(space_map_t *sm);
197void space_map_histogram_add(space_map_t *sm, range_tree_t *rt,
198    dmu_tx_t *tx);
199
200void space_map_update(space_map_t *sm);
201
202uint64_t space_map_object(space_map_t *sm);
203uint64_t space_map_allocated(space_map_t *sm);
204uint64_t space_map_length(space_map_t *sm);
205
206void space_map_write(space_map_t *sm, range_tree_t *rt, maptype_t maptype,
207    uint64_t vdev_id, dmu_tx_t *tx);
208uint64_t space_map_estimate_optimal_size(space_map_t *sm, range_tree_t *rt,
209    uint64_t vdev_id);
210void space_map_truncate(space_map_t *sm, int blocksize, dmu_tx_t *tx);
211uint64_t space_map_alloc(objset_t *os, int blocksize, dmu_tx_t *tx);
212void space_map_free(space_map_t *sm, dmu_tx_t *tx);
213void space_map_free_obj(objset_t *os, uint64_t smobj, dmu_tx_t *tx);
214
215int space_map_open(space_map_t **smp, objset_t *os, uint64_t object,
216    uint64_t start, uint64_t size, uint8_t shift);
217void space_map_close(space_map_t *sm);
218
219int64_t space_map_alloc_delta(space_map_t *sm);
220
221#ifdef	__cplusplus
222}
223#endif
224
225#endif	/* _SYS_SPACE_MAP_H */
226